diff --git a/Trigger/TrigAnalysis/TriggerMatchingTool/Root/R3MatchingTool.cxx b/Trigger/TrigAnalysis/TriggerMatchingTool/Root/R3MatchingTool.cxx
index 48da709550bd062f9bccfacaa656ab8f4e8997a2..56f5eca41e657eb5b97e5293cc1bf9540e4c4f84 100644
--- a/Trigger/TrigAnalysis/TriggerMatchingTool/Root/R3MatchingTool.cxx
+++ b/Trigger/TrigAnalysis/TriggerMatchingTool/Root/R3MatchingTool.cxx
@@ -162,6 +162,7 @@ namespace Trig
     if (cacheItr == cache.end())
     {
       const xAOD::IParticle *online = *onlineLink;
+      ATH_MSG_DEBUG("Match online " << online->type() << " to offline " << reco->type());
       bool match = online->type() == reco->type();
       if (online->type() == xAOD::Type::CaloCluster && (reco->type() == xAOD::Type::Electron || reco->type() == xAOD::Type::Photon))
       {